MathView overzealously texifying

[Alex-Jordan]

MathView is turning "in" into the "element of" symbol as in \in. So for example, a student typing inf or infinity is seeing output of the form \in f or \in f\in ity.

Not sure if it there are other scenarios as common as "inf", but it also does this for other strings. So if there were a string answer "topology", it is showing you output from \top o\log y.

Is this just a configuration issue? If so, where is MathView configured?

Or maybe it's just assumed that with string answers, the student doesn't activate MathView?

[goehle]

MathView renders whatever students put in the answer box using MathJax. Unfortunately there isn't a lot of information available on the js side for MathJax to determine what strings are special for a given problem or what they should translate to. Basically, given that all different answers are typed into a text box, it is difficult to tell if a given sequence of characters should be rendered as mathematics or as text. Some options I can think of would be

• Exporting some sort of information as data in the answer blank that MathJax could use to render stuff. This does make some of the PG components public (like what the possible strings are). This would be the more complicated solution.
• Adding a list of common WeBWorK strings to the MathView mathjax configuration so that it will at least render things like inf correctly. This would be the simpler solution but would not cover everything.

[dpvc]

I think the problem is actually that MathView uses MathJax's AsciiMath format to parse the student answer, and although AsciiMath is similar to WeBWorK's algebra notation, it is not identical. In particular, AsciiMath includes many more symbols than WeBWorK does. For example, AsciiMath has all the Greek letters (via alpha and beta, etc), and prod, sum and int, and RR for the set of reals, and -< for TeX's \prec, and in for \in, and oo for infinity, and a whole lot of others. So AsciiMath parses all kinds of things that WeBWorK doesn't. It also uses (: and :) for vectors rather than < and > (since those mean less-than and greater-than in AsciiMath). SO there are a number of significant differences between the two, and the AsciiMath results are only moderately equivalent to the MathObject results, in general.

A solution might be to have the MathJax configuration for MathView remove all the unwanted symbols from AsciiMath (and perhaps add "inf" and "infinity" for \infty, and perhaps set < and > as vector brackets). It would be rather extensive changes to the AsciiMath list, but it could be done.

[goehle]

I had not thought about removing the unwanted asciimath symbols, but that would also be necessary. I already change ** to a power and not a star, so the pathway for these changes are there.

[apizer]

One has exactly the same issues with "Show Past Answers" for the same reason. See the discussion at http://webwork.maa.org/moodle/mod/forum/discuss.php?d=3771
As far as "Show Past Answers" is concerned, I and others would much prefer to see exactly what the student entered, not a typeset version of their answer which, in the original case that let to the above post, was confusing for the instructor.

[dpvc]

I agree with Arnie; I prefer to see what the student actually typed, not a typeset version.

[goehle]

Sorry. I just thought that having it easier to read would be worth it
overall. I'll make a pull request to change it back.

[dpvc]

Could it be a choice? Perhaps a toggle on the page that would switch between the views? I'm sure there are people who prefer the typeset version (or at times do).

[mgage]

The other possibility is an overlay. In responding to entries for the current problem I chose one version (usually typeset mode) and allowed you to get the direct input as a popup by hovering over the field. This wasn't enough for some people :-) but it allowed access to the alternative format.

[apizer]

One problem, and the one Gavin first reported, is that in some cases you can not tell the difference between typeset mode and direct input if you are not specifically testing for this (and most instructors would have no reason to). If you look at the forum post, Gavin did not figure out what was going on (he didn't look hard) and it took me quite a while and a wrong guess to become aware that MathJax was the "problem" which was confirmed by Davide. In Gavin's case, Past Answers showed the answers sin(.25x), sin e(.25x), sin(.25x), and sin(.25x) and only the last answer was marked correct by WeBWorK. As Gavin reported the actual answers the student submitted were Sin(.25x), Sine(.25x), Sin(.25x), and sin(.25x). An instructor less knowledgeable about WeBWorK than Gavin would probably conclude the student entered the correct answer (sin(.25x)) and WeBWorK marked it wrong and, for some strange reason, the last time the student entered the correct answer, it was accepted. As noted in one of my and David's forum posts, right now you can easily see the actual answer the student entered, but it's not an obvious thing for an instructor to do (Gavin didn't do it and neither did I until the very end). So, if we do have a typeset mode, I would definitely want the raw input mode to be the default.

[apizer]

Another comment is whether (especially for MathView) it is feasible to substitute the WeBWorK's parser for MathJax's AsciiMath parser?

[dpvc]

MathJax runs in the browser, which means it is Javascript, but WeBWorK's parser is on the server in Perl. It would require a complete port of MathObjects to javascript to make that possible.

With MathJax v2.6 (currently in beta), it would be possible to use MathJax-node to process the math on the server to produce the HTML that MathJax would create in the browser. That could be cached just like the current image mode results. That doesn't help MathView, but it could be useful for past answers, as well as for problems in general.

[goehle]

The main issue with having a "switch" to turn typesetting on and off is that it doesn't really solve Arnie/Gavin's problem. If you suspect that its the actual answer text that is the issue you can already right click on the typeset formula to see the original answer. The issue is that unless you know or suspect that the raw answer is the problem you would never think to do that, and you wouldn't think to turn off typesetting either. Maybe building a typeset mode for mathjax which more closely mimics PG would solve the issue because it would fail on things like Sin(.25).

[dpvc]

What I had in mind was more of a preference so that people could see the form they wanted, not something intended to solve Gavin's problem directly.

As for a MathJax input that is more like MathObjects, the difficulty is that what parses and what doesn't is dependent on the answer's Context object, and that varies considerably from one context to another. E.g., in the vector contexts, "<" and ">" are delimiters for vectors, but in the Inequalities context, these are less-than and greater-than. You can't tell which way "<" and ">" are to be treated without knowing the context, so in order to make that work, you would need to have a tighter connection between the page displaying the math and the problem from which the answers came. My main objection to typesetting the answer has always been that you don't have that connection, so will misrepresent answers that are not in the basic numeric contexts. Things like currency, or scientific notation, or permutations, or other special-purpose contexts may not render correctly without the specialized knowledge of the context that the problem has but the instructor page doesn't.

[Alex-Jordan]

Returning to this after a long hiatus. @dpvc suggested that to address the MathView issue, we could remove all the unwanted symbols from AsciiMath and add a few WW-specific items back. I've looked around the MathJax and AsciiMath documentation, but I can't find how to remove things that the AsciiMath parser recognizes. Can you point me in the right direction?

I did find how to change things that the parser already recognizes, following Geoff's note above about **. However, the lines in webwork2/htdocs/js/apps/MathView/mathview.js, that are intended to make it recognize ** and output ^ are broken. Typing ** still makes an asterisk for me. I removed the var from line 24 of that file, and then typing ** makes a caret. I don't understand javascript well enough to explain this, but is this a bug/typo, and is removing var the right fix?

I also believe I have found how to add new things, like make it recognize inf and behave like oo nomrally behaves. However I can't see how to make it be case insensitive. Will I need to add INF, Inf, etc. separately?

[dpvc]

@Alex-Jordan, I think if you replace lines 23 to 32 by

MathJax.Hub.Register.StartupHook("AsciiMath Jax Config", function () {
  var AM = MathJax.InputJax.AsciiMath.AM;
  AM.symbols.splice(0,AM.symbols.length); // remove all definitions
  AM.symbols.push.apply(AM.symbols,[
    {input:"(", tag:"mo", output:"(", tex:"left(", ttype:AM.TOKEN.LEFTBRACKET},
    {input:")", tag:"mo", output:")", tex:"right)", ttype:AM.TOKEN.RIGHTBRACKET},
    {input:"[", tag:"mo", output:"[", tex:"left[", ttype:AM.TOKEN.LEFTBRACKET},
    {input:"]", tag:"mo", output:"]", tex:"right]", ttype:AM.TOKEN.RIGHTBRACKET},
    {input:"{", tag:"mo", output:"{", tex:null, ttype:AM.TOKEN.LEFTBRACKET},
    {input:"}", tag:"mo", output:"}", tex:null, ttype:AM.TOKEN.RIGHTBRACKET},
    {input:"|", tag:"mo", output:"|", tex:null, ttype:AM.TOKEN.LEFTRIGHT},
    {input:"<", tag:"mo", output:"\u2329", tex:"langle", ttype:AM.TOKEN.LEFTBRACKET},
    {input:">", tag:"mo", output:"\u232A", tex:"rangle", ttype:AM.TOKEN.RIGHTBRACKET},
    {input:"inf", tag:"mo", output:"\u221E", tex:"infty", ttype:AM.TOKEN.CONST},
    {input:"Inf", tag:"mo", output:"\u221E", tex:"infty", ttype:AM.TOKEN.CONST},
    {input:"INF", tag:"mo", output:"\u221E", tex:"infty", ttype:AM.TOKEN.CONST},
    {input:"infinity", tag:"mo", output:"\u221E", tex:"infty", ttype:AM.TOKEN.CONST},
    {input:"Infinity", tag:"mo", output:"\u221E", tex:"infty", ttype:AM.TOKEN.CONST},
    {input:"INFINITY", tag:"mo", output:"\u221E", tex:"infty", ttype:AM.TOKEN.CONST},
    {input:"none", tag:"mtext", output:"NONE", tex:null, ttype:AM.TOKEN.CONST},
    {input:"None", tag:"mtext", output:"NONE", tex:null, ttype:AM.TOKEN.CONST},
    {input:"NONE", tag:"mtext", output:"NONE", tex:null, ttype:AM.TOKEN.CONST},
    {input:"dne",  tag:"mtext", output:"DNE", tex:null, ttype:AM.TOKEN.CONST},
    {input:"Dne",  tag:"mtext", output:"DNE", tex:null, ttype:AM.TOKEN.CONST},
    {input:"DNE",  tag:"mtext", output:"DNE", tex:null, ttype:AM.TOKEN.CONST},
    {input:"sin",  tag:"mi", output:"sin", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"cos",  tag:"mi", output:"cos", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"tan",  tag:"mi", output:"tan", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"cot",  tag:"mi", output:"cot", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"sec",  tag:"mi", output:"sec", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"csc",  tag:"mi", output:"csc", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"asin", tag:"mi", output:"asin", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"acos", tag:"mi", output:"acos", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"atan", tag:"mi", output:"atan", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"acot", tag:"mi", output:"acot", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"asec", tag:"mi", output:"asec", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"acsc", tag:"mi", output:"acsc", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"asin", tag:"mi", output:"asin", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"arccos", tag:"mi", output:"arccos", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"arctan", tag:"mi", output:"arctan", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"arccot", tag:"mi", output:"arccot", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"arcsec", tag:"mi", output:"arcsec", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"arccsc", tag:"mi", output:"arccsc", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"sinh", tag:"mi", output:"sinh", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"cosh", tag:"mi", output:"cosh", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"tanh", tag:"mi", output:"tanh", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"coth", tag:"mi", output:"coth", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"sech", tag:"mi", output:"sech", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"csch", tag:"mi", output:"csch", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"asinh", tag:"mi", output:"asinh", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"acosh", tag:"mi", output:"acosh", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"atanh", tag:"mi", output:"atanh", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"acoth", tag:"mi", output:"acoth", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"asech", tag:"mi", output:"asech", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"acsch", tag:"mi", output:"acsch", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"asinh", tag:"mi", output:"asinh", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"arccosh", tag:"mi", output:"arccosh", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"arctanh", tag:"mi", output:"arctanh", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"arccoth", tag:"mi", output:"arccoth", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"arcsech", tag:"mi", output:"arcsech", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"arccsch", tag:"mi", output:"arccsch", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"exp",  tag:"mi", output:"exp", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"int",  tag:"mi", output:"int", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"sgn",  tag:"mi", output:"sgn", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"atan2",tag:"mi", output:"sgn", tex:"atan_2", ttype:AM.TOKEN.UNARY, func:true},
    {input:"abs",  tag:"mi", output:"abs", tex:null, ttype:AM.TOKEN.UNARY, rewriteleftright:["|","|"]},
    {input:"norm", tag:"mi", output:"norm", tex:null, ttype:AM.TOKEN.UNARY, rewriteleftright:["|","|"]},
    {input:"unit", tag:"mi", output:"unit", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"arg",  tag:"mi", output:"arg", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"mod",  tag:"mi", output:"mod", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"Re",   tag:"mi", output:"Re", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"Im",   tag:"mi", output:"Im", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"cong", tag:"mover", output:"\u00AF",  tex:"overline", ttype:AM.TOKEN.UNARY, acc:true},
    {input:"log",  tag:"mi", output:"log", tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"log10",tag:"mi", output:"log10", tex:"log_{10}", ttype:AM.TOKEN.UNARY, func:true},
    {input:"ln",   tag:"mi", output:"ln",  tex:null, ttype:AM.TOKEN.UNARY, func:true},
    {input:"sqrt", tag:"msqrt",output:"sqrt", tex:null, ttype:AM.TOKEN.UNARY},
    {input:"*",    tag:"mo",   output:"\u22C5", tex:"cdot", ttype:AM.TOKEN.CONST},
    {input:"/",    tag:"mfrac",output:"/", tex:null, ttype:AM.TOKEN.INFIX},
    {input:"^",    tag:"msup", output:"^", tex:null, ttype:AM.TOKEN.INFIX},
    {input:"**",   tag:"msup", output:"^", tex:null, ttype:AM.TOKEN.INFIX},
    {input:"U",    tag:"mo",   output:"\u222A", tex:"cup", ttype:AM.TOKEN.CONST},
    {input:"><",   tag:"mo",   output:"\u00D7", tex:"times", ttype:AM.TOKEN.CONST}
  ]);
});

Note that line 32 should be deleted, as it is both unnecessary and syntactically incorrect.

That should remove all the existing symbols in AsciiMath and replace them with the ones that correspond to the standard MathObjects "Full" context. It should cover the needs of all the default contexts, but won't properly handle ones like inequalities (since that defines additional operators for the relations <, >, and so on). It also won't include any new strings that get added to the context by the problem author.

Yes, you do need to do the various capitalizations, as AsciiMath doesn't have a case-insensitive mode. I've included inf, Inf, and INF (and the other values like that).

See if that doesn't do more what you want.